Chin Sing Yeap

(E)-4-Hy-droxy-N'-(4-hy-droxy-3-meth-oxy-benzyl-idene)benzohydrazide.

In the title compound, C15H14N2O4, the N=C double bond has an E configuration. The two benzene rings make a dihedral angle of 28.59 (6)°. In the crystal, molecules are linked into a three-dimensional network by intermolecular N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds and stabilized by weak C—H⋯π interactions.

9-(3,4-Dimeth­oxy­phen­yl)-3,3,6,6-tetra­methyl-4,5,6,9-tetra­hydro-3H-xanthene-1,8(2H,7H)-dione

The asymmetric unit of the title xanthene compound, C25H30O5, contains two molecules in which the pyran ring and the dimethoxyphenyl ring are nearly perpendicular to one another [dihedral angles = 86.81 (8) and 84.45 (9)°]. One of the methoxy groups in one molecule is twisted away from the phenyl ring [C—O—C—C torsion angle = −103.40 (16)°]. The pyran ring adopts a boat conformation whereas the two fused cyclohexane rings adopt envelope conformations in both molecules. In the crystal, molecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds.

Cyclo­benzaprinium salicylate

In the title molecular salt [systematic name: 3-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-N,N-dimethyl-1-propanaminium 2-hydroxybenzoate], C20H22N+·C7H5O3 −, the benzene rings of the cyclobenzaprinium cation are inclined with a dihedral angle of 61.66 (7)°. An intramolecular O—H⋯O hydrogen bond occurs within the salicylate anion, generating an S(6) ring. In the crystal, the cation and anion are linked by an N—H⋯O interaction.

{6,6'-Dimeth-oxy-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methyl-idyne)]diphenolato}nickel(II) 1.78-hydrate.

In the title complex, [Ni(C21H24N2O4)]·1.78H2O, the NiII ion has a slightly distorted planar geometry, coordinated by the two N and two O atoms of the tetradentate Schiff base ligand, with a mean deviation of 0.272 Å from the NiN2O2 plane. The N and O donor atoms are mutually cis. The dihedral angle between two benzene rings of the ligand is 38.86 (8)°. There are also three solvent water molecules, two of which lie across different crystallographic twofold rotation axes; one of these is partially occupied with a refined occupancy factor of 0.570 (7). The water molecules are linked together as tetramers in R 2 2(8) ring motifs, which also connect two neighbouring molecules of the complex through a network of O—H⋯O hydrogen bonds. The crystal structure is further stabilized by intermolecular C—H⋯O and C—H⋯π interactions, which link neighbouring molecules into extended chains along the b axis. Other interesting features of the crystal structure are the short intermolecular C⋯C [3.204 (3)–3.365 (3) Å] and the C⋯O [3.199 (2)–3.205 (2) Å] contacts which are shorter than the sum of the van der Waals radii of these atoms.

(E)-N'-(2,4,5-Trifluorobenzyl-idene)isonicotinohydrazide monohydrate.

In the Schiff base molecule of the title compound, C13H8F3N3O·H2O, the benzene ring and the pyridine ring are nearly coplanar, making a dihedral angle of 6.64 (7)°. The molecule exists in an E configuration with respect to the C=N double bond. In the crystal structure, molecules are linked via the water molecules into two-dimensional planes parallel to the ab plane through intermolecular N—H⋯O, O—H⋯O O—H⋯N and C—H⋯O hydrogen bonds.

(E)-1-(4-Fluorophenyl)ethan-1-one semicarbazone

In the title compound, C9H10FN3O, the semicarbazone group is nearly planar, with the maximum deviation of 0.044 (1) Å for one of the N atoms. The mean plane of semicarbazone group forms a dihedral angle of 30.94 (4)° with the benzene ring. The molecules are linked into a supramolecular chain by N—H⋯O hydrogen bonds formed along the c axis. The crystal structure is further stabilized by weak intermolucular C—H⋯π interactions; the closest C⋯Cg contact is 3.6505 (11) Å.

9-(3,4-Dimeth­oxy­phen­yl)-3,4,5,6,7,9-hexa­hydroxanthene-1,8(2H)-dione

In the title compound, C21H22O5, the mean planes of the pyran and dimethoxyphenyl rings are nearly perpendicular to one another, with the dihedral angle between them being 88.21 (8)°. The pyran ring adopts a boat conformation whereas the two fused cyclohexane rings adopt envelope conformations. In the crystal, molecules are linked into a three-dimensional network by intermolecular C—H⋯O hydrogen bonds.

4-(5,6-Dihydro­benzimidazo[1,2-c]quinazolin-6-yl)benzene-1,3-diol dimethyl sulfoxide monosolvate

In the title solvated benzimidazole compound, C20H15N3O2·C2H6OS, both the benzimidazole fused-ring system and the complete dimethyl sulfoxide solvent molecule are disordered over two sets of sites, in 0.750 (5):0.250 (5) and 0.882 (4):0.118 (4) ratios, respectively. The conformation of the pyrimidine ring is close to a half-chair for the major disorder component, whereas for the minor component it is close to a boat. The dihydroxyphenyl ring is almost perpendicular to the mean plane of the benzimidazole ring [dihedral angle = 87.3 (2)° for the major disorder component and 88.3 (5)° for the minor disorder component]. In the crystal, molecules are linked into layers parallel to (110) by O—H⋯N and C—H⋯O hydrogen bonds. A bifurcated O—H⋯(O,S) bond links the benzimidazole and solvent molecules.

Koetjapic acid chloro­form hemisolvate

The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS)-7-(2-carboxyethyl)-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl)-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H⋯O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H⋯O hydrogen bonds. The dimers are stacked along the c axis.

(E)-N′-(2,4,5-Trimethoxy­benzyl­idene)isonicotinohydrazide dihydrate

The asymmetric unit of the title compound, C16H17N3O4·2H2O, contains one Schiff base molecule and two water molecules. The Schiff base molecule exists in an E configuration with respect to the C=N double bond and is essentially planar, the dihedral angle between the benzene and pyridine rings being 5.48 (8)°. The three methoxy groups are also coplanar with the benzene ring [C—O—C—C torsion angles = 3.9 (2), 178.51 (15) and 0.8 (2) Å]. In the crystal structure, the water molecules link the molecules into a three-dimensional network via intermolecular N—H⋯O, O—H⋯O, O—H⋯N and C—H⋯O hydrogen bonds.